/* FCE Ultra - NES/Famicom Emulator
 *
 * Copyright notice for this file:
 *  Copyright (C) 2007 CaH4e3
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include "mapinc.h"

static uint8 reg[16], IRQa;
static uint32 IRQCount;
static uint8 *WRAM = NULL;
static uint32 WRAMSIZE;

static SFORMAT StateRegs[] =
{
	{ &IRQa, 1, "IRQA" },
	{ &IRQCount, 4, "IRQC" },
	{ reg, 16, "REGS" },
	{ 0 }
};

static void Sync(void) {
	setchr1(0x0000, reg[0] & 0xfe);
	setchr1(0x0400, reg[1] | 1);
	setchr1(0x0800, reg[2] & 0xfe);
	setchr1(0x0c00, reg[3] | 1);
	setchr1(0x1000, reg[4]);
	setchr1(0x1400, reg[5]);
	setchr1(0x1800, reg[6]);
	setchr1(0x1c00, reg[7]);
	setprg8r(0x10, 0x6000, 0);
	setprg8(0x8000, (reg[0x8] & 0xf) | 0x10);
	setprg8(0xA000, (reg[0x9] & 0x1f));
	setprg8(0xC000, (reg[0xa] & 0x1f));
	setprg8(0xE000, (reg[0xb] & 0xf) | 0x10);
	setmirror((reg[0xc] & 1) ^ 1);
}

static DECLFW(M106Write) {
	A &= 0xF;
	switch (A) {
	case 0xD: IRQa = 0; IRQCount = 0; X6502_IRQEnd(FCEU_IQEXT); break;
	case 0xE: IRQCount = (IRQCount & 0xFF00) | V; break;
	case 0xF: IRQCount = (IRQCount & 0x00FF) | (V << 8); IRQa = 1; break;
	default: reg[A] = V; Sync(); break;
	}
}

static void M106Power(void) {
	reg[8] = reg[9] = reg[0xa] = reg[0xb] = -1;
	Sync();
	SetReadHandler(0x6000, 0x7FFF, CartBR);
	SetReadHandler(0x8000, 0xFFFF, CartBR);
	SetWriteHandler(0x6000, 0x7FFF, CartBW);
	SetWriteHandler(0x8000, 0xFFFF, M106Write);
}

static void M106Reset(void) {
}

static void M106Close(void) {
	if (WRAM)
		FCEU_gfree(WRAM);
	WRAM = NULL;
}

void M106CpuHook(int a) {
	if (IRQa) {
		IRQCount += a;
		if (IRQCount > 0x10000) {
			X6502_IRQBegin(FCEU_IQEXT);
			IRQa = 0;
		}
	}
}

static void StateRestore(int version) {
	Sync();
}

void Mapper106_Init(CartInfo *info) {
	info->Reset = M106Reset;
	info->Power = M106Power;
	info->Close = M106Close;
	MapIRQHook = M106CpuHook;
	GameStateRestore = StateRestore;

	WRAMSIZE = 8192;
	WRAM = (uint8*)FCEU_gmalloc(WRAMSIZE);
	SetupCartPRGMapping(0x10, WRAM, WRAMSIZE, 1);
	AddExState(WRAM, WRAMSIZE, 0, "WRAM");

	AddExState(&StateRegs, ~0, 0, 0);
}
